The Polar RCX5 is an activity tracking watch that can be combined with various accessories to provide you with the ultimate training tool. With accessories like the H2 heart rate sensor Polar CS speed sensor W.I.N.D, and Polar s3 stride sensor, you can analyze metrics like stride and cadence to take your performance to the next level. The Polar RCX5 watch retails for $349.95 and comes with the H2 heart rate sensor.